Glenn Greenwald writes on the establishment reactions and at times systematic attacks on both Jeremy Corbyn and Bernie Sanders:
https://theintercept.com/2016/01/21/the-seven-stages-of-establishment-backlash-corbynsanders-edition/

Excerpt:
“Bernie Sanders is nowhere near as radical as Corbyn; they are not even in the same universe. But, especially on economic issues, Sanders is a more fundamental, systemic critic than the oligarchical power centers are willing to tolerate, and his rejection of corporate dominance over politics, and corporate support for his campaigns, is particularly menacing. He is thus regarded as America’s version of a far-left extremist, threatening establishment power.”

https://www.rt.com/news/329804-litvinenko-brother-britain-murder/